Sigma just lowered the price on the 70-200/2.8 OS HSM. At $1400 USD that is $1000 less than the 70-200/2.8 II. Anyone used this lens and know how it compares to the Canon 70-200/2.8 I or II or the 70-200/4 IS?

I bought the 70-200 IS USM II a couple weeks ago. All I can say is WOW. That is one heck of a piece of engineering. People go on and on about the weight and I was expecting the worst, but after using it, I don't see the weight as being a problem at all. I love it. Beautiful portraits, basketball in lousy gym lighting is no problem, and as sharp or sharper than my buddies prime when we compared the shots taken side by side with two 7Ds. The only downside is when people see you taking a shot with it, they think you're a pro and you end up with people on each side of you pulling out their cameras thinking you're doing something amazing...lol.

Bought an used 70-200 f 2.8 IS ( mark 1) today
2.8 aperture, is always a best to have , particularly at indoor shoots
IS will further help to reduce camera shake , will help to take a shoot which may be impossible to have( almost forced to use the highest ISO most of the time in indoor, night photos as i hate to use the flash)

I'm no expert, but after comparing the 70-200 f4 IS, 70-200 f2.8 IS mk1+II, and 100-400 f4.5-5.6 in a store with my 50D, I came away impressed by them all. All focused fast, but I felt the 2.8's were a tad bit quicker. I was also impressed by the huge zoom the 100-400 provides. Definately the "creepy stalker" lens of the bunch.

A while ago I was in the market for a 70-200 and I had a hard time figuring out which one I should buy. I have a load of interests (including photography, playing guitar, and gaming) which makes it hard for me to spend a lot of money on either one of them. Because the 70-200/4 is the lowest in price I originally went for this one. The image quality was supposedly better than the 2.8 versions (not including the 70-200/2.8 IS II) so this factor combined with the lowest price was decisive for me. Besides: this was already a huge improvement over my 70-300/4-5.6 III.

After two days of shooting though I already noticed that the AF (combined with my 40D which is regrettably not the best camera when it comes to AF) was too slow to my liking. Birds in flight were near impossible to track accurately, so I made the decision to try and exchange it for the 70-200/2.8. The store where I bought it luckily didn't object to this proposal and so I paid a bit extra to get the 70-200/2.8 instead.

The lens is now in my possession for about a year and I can't say that I regret paying extra for the 2.8. It's fast, it's sharp and it's build like a tank (keeping in mind that I am used to the build quality of the 70-300/4-5.6 III). The 2.8 doesn't only make this a very fast focusing lens, it also gives me more room to play with Depth of Field and since I like shooting animals in action having the 2.8 is way better than having IS. My reasoning for this is as follows: if I have a moving subject then I have not much use for IS when shutter times get too slow to actually freeze the action anyway.

So when I would get the choice between the 70-200/2.8 or the 70-200/4 IS then I would always pick the 2.8. I absolutely agree that IS is nice to have, but the advantages that 2.8 has over 4 are just to big for me to overlook. I do want to conclude that if money isn't an issue you should always pick the 70-200/2.8 IS II. This relatively new lens is just brilliant. Hope this is helpful for someone that is in the same situation I was in a year ago .